package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"os"
	"strconv"
	"sync"
	"time"

	"github.com/gin-gonic/gin"
)

type Config struct {
	Dawarich struct {
		URL   string
		Token string
	}
	HomeAssistant struct {
		URL             string
		Token           string
		DeviceTrackerID string
	}
	Auth struct {
		Username string
		Password string
	}
	Port string
}

type GPSData struct {
	Lat  string `json:"lat" form:"lat"`
	Lon  string `json:"lon" form:"lon"`
	Time string `json:"time" form:"time"`
	Alt  string `json:"alt" form:"alt"`
	Spd  string `json:"spd" form:"spd"`
	Dir  string `json:"dir" form:"dir"`
	Acc  string `json:"acc" form:"acc"`
	Batt string `json:"batt" form:"batt"`
}

type DawarichLocation struct {
	Type     string `json:"type"`
	Geometry struct {
		Type        string    `json:"type"`
		Coordinates []float64 `json:"coordinates"`
	} `json:"geometry"`
	Properties struct {
		Timestamp    string   `json:"timestamp"`
		Altitude     *float64 `json:"altitude,omitempty"`
		Speed        *float64 `json:"speed,omitempty"`
		Bearing      *float64 `json:"bearing,omitempty"`
		Accuracy     *float64 `json:"accuracy,omitempty"`
		BatteryLevel *float64 `json:"battery_level,omitempty"`
	} `json:"properties"`
}

type DawarichPayload struct {
	Locations []DawarichLocation `json:"locations"`
}

type HAState struct {
	State      string                 `json:"state"`
	Attributes map[string]interface{} `json:"attributes"`
}

type ForwardResult struct {
	Success bool   `json:"success"`
	Error   string `json:"error,omitempty"`
}

type Response struct {
	Timestamp    string `json:"timestamp"`
	ReceivedData GPSData `json:"received_data"`
	Results      struct {
		Dawarich      ForwardResult `json:"dawarich"`
		HomeAssistant ForwardResult `json:"homeassistant"`
	} `json:"results"`
}

var config Config
var httpClient = &http.Client{
	Timeout: 10 * time.Second,
}

func loadConfig() {
	config.Dawarich.URL = os.Getenv("DAWARICH_URL")
	config.Dawarich.Token = os.Getenv("DAWARICH_TOKEN")
	config.HomeAssistant.URL = os.Getenv("HOMEASSISTANT_URL")
	config.HomeAssistant.Token = os.Getenv("HOMEASSISTANT_TOKEN")
	config.HomeAssistant.DeviceTrackerID = getEnvOrDefault("HA_DEVICE_TRACKER_ID", "gps_logger")
	config.Auth.Username = os.Getenv("AUTH_USERNAME")
	config.Auth.Password = os.Getenv("AUTH_PASSWORD")
	config.Port = getEnvOrDefault("PORT", "3069")
}

func getEnvOrDefault(key, defaultValue string) string {
	if value := os.Getenv(key); value != "" {
		return value
	}
	return defaultValue
}

func parseFloat(s string) *float64 {
	if s == "" {
		return nil
	}
	if f, err := strconv.ParseFloat(s, 64); err == nil {
		return &f
	}
	return nil
}

func forwardToDawarich(gpsData GPSData) ForwardResult {
	if config.Dawarich.URL == "" || config.Dawarich.Token == "" {
		return ForwardResult{Success: false, Error: "Not configured"}
	}

	lat, err := strconv.ParseFloat(gpsData.Lat, 64)
	if err != nil {
		return ForwardResult{Success: false, Error: "Invalid latitude"}
	}

	lon, err := strconv.ParseFloat(gpsData.Lon, 64)
	if err != nil {
		return ForwardResult{Success: false, Error: "Invalid longitude"}
	}

	timestamp := gpsData.Time
	if timestamp == "" {
		timestamp = time.Now().Format(time.RFC3339)
	}

	location := DawarichLocation{
		Type: "Feature",
		Geometry: struct {
			Type        string    `json:"type"`
			Coordinates []float64 `json:"coordinates"`
		}{
			Type:        "Point",
			Coordinates: []float64{lon, lat},
		},
		Properties: struct {
			Timestamp    string   `json:"timestamp"`
			Altitude     *float64 `json:"altitude,omitempty"`
			Speed        *float64 `json:"speed,omitempty"`
			Bearing      *float64 `json:"bearing,omitempty"`
			Accuracy     *float64 `json:"accuracy,omitempty"`
			BatteryLevel *float64 `json:"battery_level,omitempty"`
		}{
			Timestamp:    timestamp,
			Altitude:     parseFloat(gpsData.Alt),
			Speed:        parseFloat(gpsData.Spd),
			Bearing:      parseFloat(gpsData.Dir),
			Accuracy:     parseFloat(gpsData.Acc),
			BatteryLevel: parseFloat(gpsData.Batt),
		},
	}

	payload := DawarichPayload{
		Locations: []DawarichLocation{location},
	}

	jsonData, err := json.Marshal(payload)
	if err != nil {
		return ForwardResult{Success: false, Error: "JSON marshal error"}
	}

	req, err := http.NewRequest("POST", config.Dawarich.URL+"/api/v1/overland/batches", bytes.NewBuffer(jsonData))
	if err != nil {
		return ForwardResult{Success: false, Error: "Request creation error"}
	}

	req.Header.Set("Authorization", "Bearer "+config.Dawarich.Token)
	req.Header.Set("Content-Type", "application/json")

	resp, err := httpClient.Do(req)
	if err != nil {
		return ForwardResult{Success: false, Error: err.Error()}
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 200 && resp.StatusCode < 300 {
		log.Println("Successfully forwarded to Dawarich")
		return ForwardResult{Success: true}
	}

	return ForwardResult{Success: false, Error: fmt.Sprintf("HTTP %d", resp.StatusCode)}
}

func forwardToHomeAssistant(gpsData GPSData) ForwardResult {
	if config.HomeAssistant.URL == "" || config.HomeAssistant.Token == "" {
		return ForwardResult{Success: false, Error: "Not configured"}
	}

	lat, err := strconv.ParseFloat(gpsData.Lat, 64)
	if err != nil {
		return ForwardResult{Success: false, Error: "Invalid latitude"}
	}

	lon, err := strconv.ParseFloat(gpsData.Lon, 64)
	if err != nil {
		return ForwardResult{Success: false, Error: "Invalid longitude"}
	}

	attributes := map[string]interface{}{
		"latitude":      lat,
		"longitude":     lon,
		"source_type":   "gps",
		"friendly_name": "GPS Logger Device",
	}

	if acc := parseFloat(gpsData.Acc); acc != nil {
		attributes["gps_accuracy"] = *acc
	}
	if alt := parseFloat(gpsData.Alt); alt != nil {
		attributes["altitude"] = *alt
	}
	if spd := parseFloat(gpsData.Spd); spd != nil {
		attributes["speed"] = *spd
	}
	if dir := parseFloat(gpsData.Dir); dir != nil {
		attributes["bearing"] = *dir
	}
	if batt := parseFloat(gpsData.Batt); batt != nil {
		attributes["battery_level"] = *batt
	}

	state := HAState{
		State:      "home",
		Attributes: attributes,
	}

	jsonData, err := json.Marshal(state)
	if err != nil {
		return ForwardResult{Success: false, Error: "JSON marshal error"}
	}

	url := fmt.Sprintf("%s/api/states/device_tracker.%s", config.HomeAssistant.URL, config.HomeAssistant.DeviceTrackerID)
	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return ForwardResult{Success: false, Error: "Request creation error"}
	}

	req.Header.Set("Authorization", "Bearer "+config.HomeAssistant.Token)
	req.Header.Set("Content-Type", "application/json")

	resp, err := httpClient.Do(req)
	if err != nil {
		return ForwardResult{Success: false, Error: err.Error()}
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 200 && resp.StatusCode < 300 {
		log.Println("Successfully forwarded to Home Assistant")
		return ForwardResult{Success: true}
	}

	return ForwardResult{Success: false, Error: fmt.Sprintf("HTTP %d", resp.StatusCode)}
}

func basicAuth() gin.HandlerFunc {
	if config.Auth.Username == "" || config.Auth.Password == "" {
		return gin.HandlerFunc(func(c *gin.Context) {
			c.Next()
		})
	}

	return gin.BasicAuth(gin.Accounts{
		config.Auth.Username: config.Auth.Password,
	})
}

func healthHandler(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{
		"status":    "healthy",
		"timestamp": time.Now().Format(time.RFC3339),
		"config": gin.H{
			"dawarich_configured":      config.Dawarich.URL != "" && config.Dawarich.Token != "",
			"homeassistant_configured": config.HomeAssistant.URL != "" && config.HomeAssistant.Token != "",
			"auth_enabled":             config.Auth.Username != "" && config.Auth.Password != "",
		},
	})
}

func gpsHandler(c *gin.Context) {
	var gpsData GPSData

	// Bind data from both query parameters and body
	if err := c.ShouldBind(&gpsData); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid GPS data"})
		return
	}

	log.Printf("Received GPS data: lat=%s, lon=%s", gpsData.Lat, gpsData.Lon)

	// Validate required fields
	if gpsData.Lat == "" || gpsData.Lon == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Missing required fields: lat, lon"})
		return
	}

	// Forward to both services concurrently
	var wg sync.WaitGroup
	var dawarichResult, haResult ForwardResult

	wg.Add(2)

	go func() {
		defer wg.Done()
		dawarichResult = forwardToDawarich(gpsData)
	}()

	go func() {
		defer wg.Done()
		haResult = forwardToHomeAssistant(gpsData)
	}()

	wg.Wait()

	response := Response{
		Timestamp:    time.Now().Format(time.RFC3339),
		ReceivedData: gpsData,
		Results: struct {
			Dawarich      ForwardResult `json:"dawarich"`
			HomeAssistant ForwardResult `json:"homeassistant"`
		}{
			Dawarich:      dawarichResult,
			HomeAssistant: haResult,
		},
	}

	// Return success if at least one service succeeded
	statusCode := http.StatusInternalServerError
	if dawarichResult.Success || haResult.Success {
		statusCode = http.StatusOK
	}

	c.JSON(statusCode, response)
}

func main() {
	loadConfig()

	// Set Gin to release mode for production
	if os.Getenv("GIN_MODE") == "" {
		gin.SetMode(gin.ReleaseMode)
	}

	r := gin.New()
	r.Use(gin.Logger(), gin.Recovery())

	// Health check endpoint (no auth required)
	r.GET("/health", healthHandler)

	// Protected endpoints
	auth := r.Group("/", basicAuth())
	{
		auth.POST("/gps", gpsHandler)
	}

	log.Printf("GPS Router service starting on port %s", config.Port)
	log.Printf("Configuration status:")
	log.Printf("- Dawarich: %t", config.Dawarich.URL != "" && config.Dawarich.Token != "")
	log.Printf("- Home Assistant: %t", config.HomeAssistant.URL != "" && config.HomeAssistant.Token != "")
	log.Printf("- Authentication: %t", config.Auth.Username != "" && config.Auth.Password != "")

	if err := r.Run(":" + config.Port); err != nil {
		log.Fatal("Failed to start server:", err)
	}
}